Which is cheaper, Claude Opus 5.5 and DeepSeek V4 Pro?

DeepSeek V4 Pro has the lowest input price. Per 1M input tokens: Claude Opus 5.5 from $4.00 and DeepSeek V4 Pro from $1.74.

Which has the larger context window, Claude Opus 5.5 and DeepSeek V4 Pro?

DeepSeek V4 Pro has the largest context window: Claude Opus 5.5 1,000,000 tokens and DeepSeek V4 Pro 1,048,576 tokens.

Which is smarter, Claude Opus 5.5 and DeepSeek V4 Pro?

Claude Opus 5.5 scores highest on the Artificial Analysis Intelligence Index: Claude Opus 5.5 58.4 and DeepSeek V4 Pro 23.1.

Can I switch between Claude Opus 5.5 and DeepSeek V4 Pro without changing my code?

Yes. All of them are served through FastRouter's OpenAI-compatible API, so switching is a change of the model parameter (anthropic/claude-opus-5.5, deepseek/deepseek-v4-pro).

Claude Opus 5.5 vs DeepSeek V4 Pro

Side-by-side pricing per provider, context window, benchmark scores and speed, all on one OpenAI-compatible API.

Estimate monthly cost for these models

Claude Opus 5.5 Anthropicanthropic/claude-opus-5.5

DeepSeek V4 Pro DeepSeekdeepseek/deepseek-v4-pro

Creator

Anthropic

DeepSeek

Released

Sep 22, 2026

Apr 24, 2026

Context window

1.05M

Max output

128K

384K

Input / 1MLowest provider price

$4.00

$1.74$1.74–$2.40 across 3

Output / 1MLowest provider price

$20.00

$3.48$3.48–$4.80 across 3

Providers

IntelligenceArtificial Analysis index

58.4

23.1

LatencyMedian time to first token

—

4.9s

ThroughputMedian tokens per second

—

<1 t/s

Accepts

Text, Image, Files

Text

Produces

Text

Tool calling

Yes

Structured output

Yes

Reasoning

Yes

Claude Opus 5.5 vs DeepSeek V4 Pro: summary

Claude Opus 5.5 and DeepSeek V4 Pro are both available through FastRouter's OpenAI-compatible API, so switching between them is a change of model id, not a new integration.

Claude Opus 5.5, from Anthropic, has a 1,000,000-token context window, costs from $4.00/1M input and $20.00/1M output tokens across 3 providers and scores 58.4 on the Artificial Analysis Intelligence Index.

DeepSeek V4 Pro, from DeepSeek, has a 1,048,576-token context window, costs from $1.74/1M input and $3.48/1M output tokens across 3 providers and scores 23.1 on the Artificial Analysis Intelligence Index.

DeepSeek V4 Pro is the cheapest on input, 2.3× cheaper than the next model, DeepSeek V4 Pro has the largest context window and Claude Opus 5.5 scores highest for intelligence.

Switch with one line

client = OpenAI(base_url="https://api.fastrouter.ai/api/v1", api_key="<FASTROUTER_API_KEY>") client.chat.completions.create(model="anthropic/claude-opus-5.5", messages=[...]) # or client.chat.completions.create(model="deepseek/deepseek-v4-pro", messages=[...])

Full API docs

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More comparisons

Benchmark scores sourced from ArtificialAnalysis